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Keywords

Subject Areas

Electrical engineering; Computer science

Abstract

This thesis summarizes research on the design and implementation of the unequal error protection (UEP) mechanism for the RaptorQ forward error correction (FEC) scheme. As part of this research, existing UEP mechanisms for various fountain codes were evaluated. Two new UEP methods were proposed for the RaptorQ coding scheme, and these methods were designed with the assumption that all of the symbols in a source block have the same priority. The first method, known as priority based overhead number (PBON), was based on the priority encoding transmission model, wherein the error-correction capability was altered by making the number of overhead symbols proportional to the priority of the information symbols. This method was extended to the RaptorQ codes with some changes and evaluated for failure probability and performance. The second method, known as priority based precode ratio (PBPR), was designed by changing the precode properties of the RaptorQ codes. The ratio of precode symbols to Luby-Transform symbols in the RaptorQ codes was changed to achieve different error correction capabilities for each priority group. The scheme with the higher number of precode symbols provided superior error-correction capabilities compared to those with fewer precode symbols. Both methods were empirically verified through

simulation in the C++ programming language. The results demonstrated that the higher-importance class depicted a better error-correction capability than the lower-importance class.